Saltwater ****es me off

[canadianbudz604]

I live not far from bear creek as well. Feeding schedule is once every 2 days (1/4 cube of mysis, and nls pellets) I don't over feed. Only as much as the fish and crew eats. No sump, a small Biocube skimmer , running only a small bag of fluval carbon in an aquaclear 70. For flow I've got the aquaclear, 425?gph koralia, and a koralia nano. My tank was doing very well before the API filter. Crazy amounts of growth. Only thing I've changed up was the water source. If I change 50% of the water will it shock anything? I always match my water up before using it. I don't want to go digging in the sand to find the nassatius snails, but I will if I have to. On a side note my hammer coral and soft corals look great